Bitrophic effects of artificial diets of American bollworm (Helicoverpa armigera H.) on different biological aspects of Bracon hebetor Say

Abstract

The effects of different artificial diets were observed on the biological parameters (sex ratio, emergence/survival, development time) of Bracon hebetor (Say) (Hymenoptera: Braconidae) against the American bollworm (Helicoverpa armigera) under laboratory conditions at 26 ± 1 °C, 65 ± 5% R.H. Four diets were comprised of gram flour, rice flour, wheat flour and corn flour. Outcome of present investigation revealed that egg to adult development time of B. hebetor ranged from 7.65 to 14 days for pre-adult durations of both males and females on corn and gram flour diets respectively. B. hebetor Female’s percentage was significantly affected by the host diet. Significant female percentage was observed on gram flour diet (59.93%) and lowest on rice flour (47.16%). Adult parasitoids survival was significantly higher on gram flour diet (61.70 ± 0.50) and lowest on corn flour diet (28.03 ± 0.29). Egg-larvae-pupae survival was significantly higher on the gram flour diet (81.20 ± 1.56, 89.70 ± 1.65 and 88.10 ± 0.82, respectively) compared to other treatments. Gram flour was found to be the best suited diet for parasitoid rearing. Results of this study may be used to improve mass-rearing programs of B. hebetor. Keywords: Biotrophic effects, Artificial diets, Helicoverpa armigera, Bracon hebetor